Inflatable towable float

ABSTRACT

A towable structure is configured to be towed behind a boat while floating above the surface of a body of water. In one implementation, the towable structure has a platform for supporting one or more passengers thereon extending between or otherwise supported by at least three water engaging base members. The base members are buoyant to extend above the surface of the body of water. The platform extends from a location sufficiently elevated on each of the base members so that the platform stays out of the water under normal operation when unloaded and when supporting one or more passengers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No. 10/882,080 filed Jun. 30, 2004 and of U.S. Ser. No. 11/321,277 filed Dec. 28, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed generally to structures that float in water and, more particularly, to inflatable structures that can be towed by boat and support a passenger.

2. Description of the Related Art

Floatable structures include those that can be inflated and towed by boat while supporting a passenger. In general, a towed structure being towed by a tow boat imparts drag force to the tow boat due to the towed structure being pulled through water. Consequently, the conventional towed structure may be significantly limited in size to keep drag force to a reasonable level. Unfortunately, both size limitations and unreasonable levels of drag forces can detrimentally impact usefulness of the conventional towed structures.

BRIEF SUMMARY OF THE INVENTION

The present invention resides in a structure to be towed in a body of water. Aspects include a first member having an upper surface and a lower surface. At least three spaced apart buoyant second members extend from the first member and have sufficient buoyancy such that when the second members are placed in the body of water, the first member remains elevated above the body of water to define an air space between the lower surface of the first member and the body of water when the body of water has a level water surface.

Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a front isometric view of a first towable structure according to aspects of the present invention.

FIG. 2 is a top plan view of the first towable structure of FIG. 1.

FIG. 3 is a rear elevational view of the first towable structure FIG. 1.

FIG. 4 is a bottom plan view of the first towable structure of the FIG. 1.

FIG. 5 is a top plan view of a second towable structure according to aspects of the present invention.

FIG. 6 is a side elevational plan view of the second towable structure of FIG. 5.

FIG. 7 is a bottom plan view of the second towable structure of FIG. 5.

FIG. 8 is a top plan view of a third towable structure according to aspects of the present invention.

FIG. 9 is a side elevational plan view of the third towable structure of FIG. 8.

FIG. 10 is a bottom plan view of the third towable structure of FIG. 8.

FIG. 11 is a top front isometric view of a fourth towable structure according to aspects of the present invention.

FIG. 12 is a bottom front isometric view of the fourth towable structure of FIG. 11.

FIG. 13 is a bottom front view of the fourth towable structure at FIG. 11.

FIG. 14 is a top front isometric view of a fifth towable structure according to aspects of the present invention.

FIG. 15 is a bottom rear isometric view of the fifth towable structure of the FIG. 14.

FIG. 16 is a side elevational plan view of the fifth towable structure of FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

As will be discussed in greater detail herein, a towable structure is configured to be towed behind a boat while floating above the surface of a body of water. In one implementation, the towable structure has a platform for supporting one or more passengers thereon extending between or otherwise supported by at least three water engaging base members. The base members are buoyant to extend above the surface of the body of water. The platform extends from a location sufficiently elevated on each of the base members so that the platform stays out of the water under normal operation when unloaded and when supporting one or more passengers. The total combined surface area of those portions of the base members in contact with the body of water is typically much less than that portion of the surface area of the platform that would contact the body of water if not supported by the base members. Consequently, the towable structure may impart less drag force on the tow boat than a conventional towable structure for an equivalent amount of surface area available to support passengers or objects being carried by the towable structure.

A first towable structure 10 implemented according to aspects of the present invention to float in a body of water 12 is depicted in FIG. 1 as having a platform 14 having a upper surface 14 a for supporting passengers and objects (not shown) and a lower surface 14 b facing the body of water. The platform 14 of the first towable structure 10 approximates a general triangular shape (better shown in FIG. 2) having corners that are coupled to three base members 16. The platform 14 extends between the three base members 16 so as to be elevated above the body of water 12 under normal operating conditions. The three base members 16 are spaced apart from each other and attached to the platform 14 to hold the platform raised above the water to define an air space between the lower surface 14 b and the water, and support one or more passengers in an elevated position above the water. As such, the passengers are positioned on the platform 14 spanning between the water engaging base members 16 without the platform engaging the water. The lower surface 14 b of the platform 14 is preferably held by the base members 16 at least two inches above the water when unloaded without being pulled, and also when loaded with a passenger when being pulled by a tow boat, so as to carry the passenger above and out of the water and without the lower surface 14 b dragging in the water.

The platform 14 and the base members 16 are formed by separately inflatable bladders or can be molded as a single bladder. The first towable structure 10 may also be implemented with one or more components being non-inflatable such as with foam. In a particular implementation, the first towable structure 10 is made of inflatable bladders 15 that are inserted into a shell 17 being formed to take on the shape of the first towable structure.

The base members 16 are depicted for the first towable structure as each approximating a general spherical shape. The platform 14 includes handles 18 and the base members 16 also include handles 20 to provide grip support for passengers of the first towable structure 10. At least one of the base members 16 has an attachment point 22 to receive a rope, cable, or other flexible member 24 used to tow the first towable structure by a boat (not shown). As shown in FIG. 2, the platform 14 has at least one attachment point 26, which can also be used for securing a flexible member 24 (such as a rope, cable, or other flexible member (not shown)) to the first towable structure to be towed by a tow boat as an alternative to the attachment point 22 described above.

As shown in FIG. 3, to provide additional stability to the platform 14, at least one flexible strut or support member 27 is coupled to each of the base members 16 and to the lower surface 14 b of the platform in such a way to counteract moment forces M to prevent the base members from rotating upward about the platform and to prevent the platform from being lowered with respect to the base members. This provides rigidity to the front towable structure 10. The support members 27 can be made of a fabric including a webbing material as long as the material is sufficiently strong with regard to the moment forces M.

In a depicted exemplary implementation with the body of water 12 having no waves or other movement as shown in FIG. 3, the body of water would have a level water surface 28. When the first towable structure 10 is in an unloaded state not carrying passengers and/or objects with the body of water 12 in the still condition, each of the base members 16 extend below the level water surface 28 to a certain amount with a submerged portion 30 of the base member being below the level water surface and an unsubmerged portion 32 of the base member being above the level water surface.

In the exemplary implementation, the first towable structure weighs approximately 62.4 pounds thereby displacing approximately a cubic foot of the body of water 12. With the three base members 16 each approximating a spheroid with a diameter of 3.5 feet, each of the three base members would be submerged into the body of water 12 a vertical amount of approximately 3 inches thereby each displacing approximately a third of a cubic foot of water a piece and having surface contact with the body of water over approximately 2.75 square feet of each. The three base members 16 thus present a total of 8.25 square feet of surface contact with the body of water 12. In the exemplary implementation, the upper surface 14 a of the platform 14 is sized to have approximately 26.4 square feet of surface area. Consequently, in this implementation the surface area of contact for the three base members with the body of water 12 is 31% of the surface area of the upper surface 14 a of the platform 14, which could beneficially reduce the amount of drag force experienced by the first towable structure 10 compared with a towable structure having a surface area equal to the surface area of the upper surface 14 a of the platform 14 contacting the water. Other implementations have a surface area of contact for three or another number of base members greater than three with the body of water include a ratio of over 31% such as no more than 40% or no more than 50% of the surface area of the upper surface 14 a of the platform 14 or some other upper surface of another shaped body supporting passengers and/or objects.

When loaded within its design range for proper operation, with one or more passengers, the base members 16 displace more water and sit lower in the water, but not so much as to allow the lower surface 14 b of the platform 14 to significantly drag in the water and thus the first towable structure 10 experiences less drag than would be experienced by the platform 14 if fully contacting the water. The lower surface 14 b of the platform 14 is held above the water surface 28 to define the air space between the water and the lower surface 14 b, above which the passengers are positioned on the upper surface 14 a of the platform 14. It is to be understood that a passenger riding on the platform 14 may allow a portion of his or her body to extend outward beyond the upper surface 14 a and to even touch the water if desired.

Although the base members 16 of the first towable structure 10 are depicted as approximating spheroids, other implementations have other shapes for the base members. For instance, the base members 16 could be shaped so that only those portions of the base members (know herein as the water contact portions of the base members) that are intended to be in contact with the body of water 12 during intended towing conditions (such as within gross weight ratings, towing speed limits, and acceptable wave conditions) would approximate portions of a spheroid or more generally portions of an ellipsoid or another curved body surface. More generally, a requirement in some implementations would only mandate that the submerged portion 30 (being depicted in FIGS. 3 and 4 as a cap portion of a spheroid) be a cap portion of some form of an ellipsoid or other curved body surface (an ellipsoid being a general class that includes but is not limited to spheroids). Other shapes for the base members 16 may also be used including shapes with one or more flat portions.

Some implementations use cylindrical cap portions, ellipsoid cap portions, or other shaped cap portions for either the water contact portions or at least the submerged portions 30 in which each of these cap portions are shaped such that any dimension passing through the centroid of a first area defined by the surface of the cap portion intersecting a first plane parallel to the plane of the water level 28 would be no more than 20% greater than any other dimension of the first area passing through the centroid 39 of the first area. In these implementations the first towable structure 10 can skim over the water somewhat like a rudderless craft. For instance, if the tow boat turns sharply, the first towable structure 10 of these implementations is more likely to momentarily move in a direction other than the direction of the tow boat so that the base members 16 of the first towable structure would avoid digging into the water to such an extent as to cause the first towable structure to flip or otherwise assume an undesirable condition.

A second towable structure 40 shown in FIG. 5 resembles a tire inner tube in shape having a ring like structure with an upper surface 41 surrounding a central opening 42 and having an attachment point 44 to couple to a flexible member (not shown) for towing. The upper surface 41 may be covered with a material cover spanning across the central opening 42 to define a support platform without a hole. The second towable structure 40 has five (better shown in FIG. 7) base members 50 that protrude from a lower surface 52 of the second towable structure 40 to raise the lower surface above the body of water 12. The second towable structure 40 is shown in FIG. 6 unloaded and sitting in the still body of water 12 with a level water surface 58. The submerged portions 54 of the base members 50 are ellipsoidal cap shaped as better shown in FIG. 7. In other implementations, the second towable structure 40 may have a different number of base members 50 and can be of other shapes similar to that described above concerning the submerged portions 30 of the base members 16 of the first towable structure 10.

A third towable structure 60 shown in FIG. 8 is disk shaped with a circular upper surface 62 having side wall 64 with an attachment point 66 for coupling to a flexible member (not shown) for towing. The third towable structure 60 further has six (better shown in FIG. 10) base members 70 extending from a lower surface 72 of the third towable structure as also shown in FIG. 9. A submerged portion 74 of each of the base members 70 extends below a level water surface 68 to elevate the lower surface 72 above the level water surface as shown in FIG. 9. As depicted, the base members 70 are shaped as portions of spheroids with the submerged portions 74 being spheroid caps as shown in FIGS. 9 and 10. In other implementations, the third towable structure 60 may have a different number of the base members 70 and can be of other shapes similar to that described above concerning the submerged portions 30 of the base members 16 of the first towable structure 10.

A fourth towable structure 80 shown in FIG. 11 has an elliptically shaped upper surface 82 having a side wall 84 with an attachment point 86 for coupling to a flexible member (not shown) for towing. An elongated cylindrically shaped member 88 protrudes above and extends longitudinally along the elongated dimension of the upper surface 82 to provide support to one or more passengers of the fourth towable structure 80. The fourth towable structure 80 further has four (better shown in FIG. 12) base members 90 extending from a lower surface 92 of the fourth towable structure. A submerged portion 94 of each of the base members 90 extends below a level water surface 96 to elevate the lower surface 92 above the level water surface as shown in FIGS. 11 and 12. As depicted, the base members 90 are shaped as portions of spheroids with the submerged portions 94 being spheroid caps as shown in FIGS. 11-13. In other implementations, the fourth towable structure 80 may have a different number of base members 90 and can be of other shapes similar to that described above concerning the submerged portions 30 of the base members 16 of the first towable structure 10.

A fifth towable structure 100 shown in FIG. 14 has a lounge chair portion 101 having an upper torso portion 101 a and a lower torso portion 101 b. The upper torso portion 101 a has a first upper surface portion 102 to support an upper torso portion of a passenger. The lower torso portion 101 b has a second upper surface portion 104 to support a lower torso portion of the passenger. An attachment point 106 is coupled to the lower torso portion 101 b of the lounge chair portion 101 to couple to a flexible member (not shown) for towing. As shown in FIGS. 14-16, the lounge chair portion 101 of the fifth towable structure 100 is supported above a level water surface 108 by a front base member 110 extending from a first lower surface 112 of the lower torso portion 101 b and having a front submerged portion 113 below the level water surface and by two side base members 114 attached to two sides 116 of the lower torso portion 101 b and having side submerged portions 115 below the level water surface.

As depicted, the front base member 110 is shaped as a spheroid cap whereas the side base members 114 are shaped as full spheroids. Consequently, the front submerged portion 113 and the side submerged portions 115 are shaped as spheroid caps. The fifth towable structure 100 also has a rear base member 118 extending from a second lower surface 120 of the upper torso portion 101 a to support the upper torso portion of the lounge chair portion 101 above the level water surface when the weight distribution of a load supported by the lounge chair portion is such that the lounge chair portion tips rearward sufficiently so that the second lower surface 120 is moved toward the water surface. In other implementations of the fifth towable structure 100, the front submerged portion 11 3 and the side submerged portions 115 can be of other shapes similar to that described above concerning the submerged portions 30 of the base members 16 of the first towable structure 10.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. 

1. A structure to be towed in a body of water while supporting a passenger, the structure comprising: an air inflatable, non-rigid platform member having an upper surface and a lower surface spaced apart from the upper surface with an air-filled space therebetween, with the upper surface forming a platform sized to flexibly support at least one rider thereon; and at least three spaced apart buoyant air inflatable, non-rigid support members, the support members being non-rigidly but securely attached to the platform member with the support members extending downward therefrom, the support members in combination having sufficient buoyancy to hold the platform member elevated above the body of water while supporting the passenger when the support members are placed in the body of water and to define an air space between the lower surface of the platform member and the body of water when the body of water has a level water surface.
 2. A water sport play structure to be towed in a body of water while supporting a passenger, the structure comprising: a non-rigid platform member having an upper surface forming a platform sized to flexibly support at least one rider thereon; and at least three spaced apart buoyant air inflatable, non-rigid support members non-rigidly but securely retained adjacent to the platform member during towing of the structure without use of rigid support frame members, the support members extending downward from adjacent the platform member and being positioned about the platform member to stably support the platform in a desired orientation with the at least one rider thereon, the support members in combination having sufficient buoyancy to hold the platform member elevated above the body of water while supporting the passenger when the support members are placed in the body of water and to define an air space between a lower surface of the platform member and the body of water when the body of water has a level water surface.
 3. The structure of claim 2 wherein the support members each comprise an inflatable buoyant bladder coupled to the platform member by a flexible shell.
 4. A water sport play structure to be towed in a body of water while supporting a passenger, the structure comprising: a non-rigid platform member having an upper surface forming a platform sized to flexibly support at least one rider thereon; at least three spaced apart buoyant support members; and a flexible shell having the platform member and the support members positioned and securely retain therein during towing of the structure without use of rigid support frame members, the flexible shell non-rigidly retaining platform member relative to the support members, the support members extending downward from adjacent the platform member and having sufficient buoyancy such that when the support members are placed in the body of water, the platform member remains elevated above the body of water while supporting the passenger to define an air space between a lower surface of the platform member and the body of water when the body of water has a level water surface, wherein the support members are each positioned within a support member portion of the flexible shell and coupled to the platform member by the support member portion of the flexible shell.
 5. The structure of claim 4 wherein the platform member is positioned within a platform member portion of the flexible shell.
 6. The structure of claim 5 wherein a flexible strut is attached to and extends between each support member portions of the flexible shell and the platform member portion of the flexible shell.
 7. The structure of claim 6 wherein the flexible strut is attached to each support member portion of the flexible shell at a location below the platform member and attached to a lower side of the platform member portion of the flexible shell at a location below the platform member.
 8. The structure of claim 4 further including a tow line attachment attached to the flexible shell.
 9. The structure of claim 8 wherein the tow line attachment is attached to at least one of the support member portions of the flexible shell.
 10. The structure of claim 9 wherein the platform member has at least three sides defining at least three corners with at least one of the support members positioned at each corner.
 11. The structure of claim 8 wherein the tow line attachment is attached to the platform member portion of the flexible shell.
 12. The structure of claim 4 wherein the support members are substantially spherical in shape.
 13. The structure of claim 12 wherein the platform member is positioned adjacent a mid-portion of each of the substantially spherical support members.
 14. A structure to be towed in a body of water, the structure comprising: a first member having an upper surface and a lower surface, wherein at least a portion of the first member has a chair shape with an upper torso portion and a lower torso portion, the lower torso portion having a lower surface and two side surfaces; and at least three spaced apart buoyant second members extending from the first member and having sufficient buoyancy such that when the second members are placed in the body of water, the first member remains elevated above the body of water to define an air space between the lower surface of the first member and the body of water when the body of water has a level water surface, different ones of the second members extending from the lower surface of the lower torso portion and each of the two side surfaces of the lower torso portion to elevate the lower surface of the lower torso portion above the level water surface.
 15. The structure of claim 14 further including a tow line attachment attached to the first member.
 16. The structure of claim 14 wherein the first member is an air inflatable, non-rigid member.
 17. The structure of claim 14 wherein the first member is an air inflatable, non-rigid first bladder with the upper surface forming a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid second bladders, and further including a flexible shell and a tow line attachment attached to the shell, the shell having the first bladder and the second bladders positioned and securely retain therein during towing of the structure without use of rigid support frame members, the first bladder being non-rigidly retained relative to the second bladders, the second bladders extending from the location of the first bladder downward.
 18. The structure of claim 14 wherein the upper surface of the first member is non-rigid and forms a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid support members, and further including a fabric shell having the first member and the support members positioned and securely retain therein during towing of the structure without use of rigid support frame members, the fabric shell non-rigidly retaining the first member relative to the support members, the support members extending downward from adjacent the first member, the support members each being positioned within and coupled to the first member by at least one portion of the fabric shell.
 19. The structure of claim 18 wherein the first member is an air inflatable, non-rigid member.
 20. A chair shaped structure to be towed in a body of water, the structure comprising: a chair shaped member with an upper surface and a lower surface, and having an upper torso portion and a lower torso portion, the lower torso portion having a lower surface and two side surfaces; and first, second and third buoyant members, the first buoyant member being positioned to a left side of the lower torso portion and extending downward therefrom, the second buoyant member being positioned to a right side of the lower torso portion and extending downward therefrom, and the third buoyant member being positioned under the lower surface of the chair shaped member at the lower torso portion and extending downward therefrom, the first, second and third buoyant members in combination having sufficient buoyancy such that when the first, second and third buoyant members are placed in the body of water, the chair shaped member remains elevated above the body of water to define an air space between the lower surface of the chair shaped member and the body of water when the body of water has a level water surface.
 21. The structure of claim 20 further including a fourth buoyant member positioned under the lower surface of the chair shaped member at the upper torso portion and extending downward therefrom.
 22. The structure of claim 20 wherein the chair shaped member is an air inflatable, non-rigid member.
 23. A structure to be towed in a body of water, the structure comprising: a first member having an upper surface and a lower surface, wherein at least a portion of the first member is elliptically shaped and another portion of the first member is cylindrically shaped, the cylindrically shaped portion being coupled to the elliptically shaped portion along a portion of the upper surface of the first member; and at least three spaced apart buoyant second members extending from the first member and having sufficient buoyancy such that when the second members are placed in the body of water, the first member remains elevated above the body of water to define an air space between the lower surface of the first member and the body of water when the body of water has a level water surface.
 24. The structure of claim 23 further including a tow line attachment attached to the first member.
 25. The structure of claim 23 wherein the first member is an air inflatable, non-rigid member.
 26. The structure of claim 23 wherein the first member is an air inflatable, non-rigid first bladder with the upper surface forming a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid second bladders, and further including a flexible shell and a tow line attachment attached to the shell, the shell having the first bladder and the second bladders positioned and securely retain therein during towing of the structure without use of rigid support frame members, the first bladder being non-rigidly retained relative to the second bladders, the second bladders extending from the location of the first bladder downward.
 27. The structure of claim 23 wherein the upper surface of the first member is non-rigid and forms a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid support members, and further including a fabric shell having the first member and the support members positioned and securely retain therein during towing of the structure without use of rigid support frame members, the fabric shell non-rigidly retaining the first member relative to the support members, the support members extending downward from adjacent the first member, the support members each being positioned within and coupled to the first member by at least one portion of the fabric shell.
 28. The structure of claim 27 wherein the first member is an air inflatable, non-rigid member.
 29. A structure to be towed in a body of water, the structure comprising: a first member having an upper surface and a lower surface, wherein at least a portion of the first member is ring shaped; and at least three spaced apart buoyant second members extending from the first member and having sufficient buoyancy such that when the second members are placed in the body of water, the first member remains elevated above the body of water to define an air space between the lower surface of the first member and the body of water when the body of water has a level water surface.
 30. The structure of claim 29 further including a tow line attachment attached to the first member.
 31. The structure of claim 29 wherein the first member is an air inflatable, non-rigid member.
 32. The structure of claim 29 wherein the first member is an air inflatable, non-rigid first bladder with the upper surface sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid second bladders, and further including a flexible shell and a tow line attachment attached to the shell, the shell having the first bladder and the second bladders positioned and securely retain therein during towing of the structure without use of rigid support frame members, the first bladder being non-rigidly retained relative to the second bladders, the second bladders extending from the location of the first bladder downward.
 33. The structure of claim 29 wherein the first member has a central aperture with a non-rigid cover extending over the aperture and forming a platform with a platform upper surface sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid support members.
 34. The structure of claim 29 wherein the upper surface of the first member is non-rigid and forms a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid support members, and further including a fabric shell having the first member and the support members positioned and securely retain therein during towing of the structure without use of rigid support frame members, the fabric shell non-rigidly retaining the first member relative to the support members, the support members extending downward from adjacent the first member, the support members each being positioned within and coupled to the first member by at least one portion of the fabric shell.
 35. The structure of claim 34 wherein the first member has a central aperture and the fabric shell extends over the aperture and forms the platform sized to flexibly support the at least one rider thereon.
 36. A structure to be towed in a body of water, the structure comprising: a first member having an upper surface and a lower surface, wherein at least a portion of the first member is disk shaped and the upper surface of the first member has a circular shape; and at least three spaced apart buoyant second members extending from the first member and having sufficient buoyancy such that when the second members are placed in the body of water, the first member remains elevated above the body of water to define an air space between the lower surface of the first member and the body of water when the body of water has a level water surface.
 37. The structure of claim 36 further including a tow line attachment attached to the first member.
 38. The structure of claim 36 wherein the first member is an air inflatable, non-rigid member.
 39. The structure of claim 36 wherein the first member is an air inflatable, non-rigid first bladder with the upper surface forming a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid second bladders, and further including a flexible shell and a tow line attachment attached to the shell, the shell having the first bladder and the second bladders positioned and securely retain therein during towing of the structure without use of rigid support frame members, the first bladder being non-rigidly retained relative to the second bladders, the second bladders extending from the location of the first bladder downward.
 40. The structure of claim 36 wherein the upper surface of the first member is non-rigid and forms a platform sized to flexibly support at least one rider thereon, and wherein the second members are air inflatable, non-rigid support members, and further including a fabric shell having the first member and the support members positioned and securely retain therein during towing of the structure without use of rigid support frame members, the fabric shell non-rigidly retaining the first member relative to the support members, the support members extending downward from adjacent the first member, the support members each being positioned within and coupled to the first member by at least one portion of the fabric shell.
 41. The structure of claim 40 wherein the first member is an air inflatable, non-rigid member. 